Answer:
Step-by-step explanation:
let the radius be r and the slant height be L
then first of all: L^2 = r^2 + 9^2
= r^2 + 81
Surface area = πrL = n
volume = (1/3)πr^2 (9) = 3πr^2 = n
then 3πr^2 = πrL
3r = L , then in L^2 = r^2 + 81
9r^2 = r^2 + 81
8r^2 = 81
r = 9/√8
L^2 = 81/8 + 81 = 729/8
L = √1458/4
cos(baseangle) = (9/√8) / (√1458/4)
= 1/3
angle of base = appr 70.5°
check my arithmetic
